In today's point-to-point communications, wireless communication systems provide many advantages over conventional systems. The communication systems provide efficient allocation of limited communication resources, for example, radio frequency (RF) channels, to a large number of subscribers that use the communication devices, such as cell phones and mobile/portable radios, to access various communication services.
In a wireless communication system, a plurality of communication devices communicate voice and data messages via one or more base stations that provide the air interface and radio link to the communication devices. A communication resource controller is responsible for allocation of the RF channels and other system resources. Generally, the resource controller controls the type of information transmitted to the communication devices and the way it is encoded. For example, control messages are communicated over control channels, and voice and data messages are communicated over voice or data (also known as traffic) channels. The resource controller, upon reception of an inbound channel request from one of the communication devices or when the communication device is being called, allocates the available resources to the communication device.
In some communication systems, the availability of system resources impacts access latency to the communication services. That is, when the communication resources are fully utilized, the subsequent communication devices that request service are placed in queue until the system resources become available again Normally when a specified maximum allowed queue size is reached, further resource requests are ignored or denied.
Service availability corresponds to the probability of communication service (e.g., voice or data service) being available to service subscribers. For example, the communication services may require placing calls or connecting to a private or public network, such as the Internet. The precise definitions of availability are often documented in a contract between an equipment vendor and a customer service provider. The definitions usually specify the parameters that impact the availability of the system. For example, a web connection within 45 seconds can be specified to satisfy a system availability definition. Alternatively, producing ringing tones for a placed call within 30 seconds could be used as another definition for system availability.
Availability is often measured in “nines”. To obtain this measure the availability is first expressed as a percentage. An availability of 99.99% is four-nines availability. Some system operators try to achieve what is called a “5-nines” availability that corresponds to providing uninterrupted service at least 99.999% of the time. Because of the need for additional resources, such availability may come at a price to those subscribers that do not require such a high availability. It is known to trade off service availability against other system parameters, such as maximum number of supported users, latency, flexibility, efficiency, etc.
Conventionally, availability is specified when a system is purchased. In more advanced systems a purchased system can be configured at startup to provide a certain availability. Moreover, technology exists to calculate how availability depends on system configuration and parameters. Known systems offer subscribers a range of system configurations that are designed to support a defined availability for a specified price or subscription fee, where each system is configured and customized at the beginning of service. However, if a subscriber later realizes that a different service availability is needed, a new configuration and customization process must be initiated. As such, the known processes for providing customized communication services are inflexible.
Accordingly, there exists a need to provide flexible and adjustable communication services to subscribers, without having to re-customize, every time subscriber service availability needs changes, which is a cumbersome and costly process Preferably the availability can be varied while the system is operating.